This proposal seeks continued support for a prospective study of behavior and psychosocial factors in a cohort of 1,000 homosexual men at risk for Acquired Immune Deficiency Syndrome (AIDS). Support from NIAID provides biomedical investigation every six months in order to document the natural history of HIV infection. The applicants have received NIMH support since June, 1985 for psychosocial investigation of the same cohort. Over 95% of those participating in the NIAID-funded study agreed to participate in the psychosocial Coping and Change Study (CCS). A supplemental cohort of 200 Black homosexual men is currently being recruited. Data has been obtained by asking participants to complete a self- administered questionnaire two weeks following their biannual biomedical studies. The CCS assessment focuses on sexual behavior, psychological and social functioning, concurrent stresses, personal resources and coping strategies, and idiosyncratic characteristics of the AIDS crisis. In addition, a behavioral interview would be conducted in a random 25% subsample of the cohort every six months. The simultaneous collection of biomedical and psychosocial data in the same cohort will provide a unique opportunity to investigate two important research questions: 1) To what extent is behavioral risk reduction occurring and what are the determinants of such behavior in this cohort of homosexual men? Analyses to date suggest that behavioral changes may be relatively unstable in a significant proportion of the cohort (approximately one-quarter) but that long-term valid behavioral typologies can be identified and predictive models developed. Such prospective data are theoretically valuable and have important practical implications for designing and implementing preventive interventions. 2) To what extent is psychological or social functioning impaired in response to the threat of AIDS and what are the determinants of such dysfunction? The crisis of AIDS has meant the introduction of a previously unanticipated and potentially severe stressor into the lives of all those at risk. Although epidemiologic and policy attention tends to focus on behavioral issues, it is important to understand more generally how men are appraising and coping with this crisis, how social and personal resources influence adaptation, and the extent to which dysfunction is occurring.